Google, a noted supporter of open-source software, has pledged not to sue anyone developing, distributing, or using open-source software that uses any of a specified number of Google patents unless attacked first.

At Google we believe that open systems win. Open-source software has been at the root of many innovations in cloud computing, the mobile web, and the Internet generally. And while open platforms have faced growing patent attacks, requiring companies to defensively acquire ever more patents, we remain committed to an open Internet—one that protects real innovation and continues to deliver great products and services.

Today, we’re taking another step towards that goal by announcing the Open Patent Non-Assertion (OPN) Pledge: we pledge not to sue any user, distributor or developer of open-source software on specified patents, unless first attacked.

The company has launched the pledge with just 10 patents, all of them already widely used, but it intends to add to these over time. Google said it hopes other patent owners will follow its example.

The Next Web observed that the pledge is similar to the one announced last year by Twitter, though Google doesn’t go quite as far. Twitter effectively handed over the patented technologies for anyone to use, while Google retains control and simply promises not to sue.